The dopamine motive system: implications for drug and food addiction.

Behaviours such as eating, copulating, defending oneself or taking addictive drugs begin with a motivation to initiate the behaviour. Both this motivational drive and the behaviours that follow are influenced by past and present experience with the reinforcing stimuli (such as drugs or energy-rich foods) that increase the likelihood and/or strength of the behavioural response (such as drug taking or overeating). At a cellular and circuit level, motivational drive is dependent on the concentration of extrasynaptic dopamine present in specific brain areas such as the striatum. Cues that predict a reinforcing stimulus also modulate extrasynaptic dopamine concentrations, energizing motivation. Repeated administration of the reinforcer (drugs, energy-rich foods) generates conditioned associations between the reinforcer and the predicting cues, which is accompanied by downregulated dopaminergic response to other incentives and downregulated capacity for top-down self-regulation, facilitating the emergence of impulsive and compulsive responses to food or drug cues. Thus, dopamine contributes to addiction and obesity through its differentiated roles in reinforcement, motivation and self-regulation, referred to here as the 'dopamine motive system', which, if compromised, can result in increased, habitual and inflexible responding. Thus, interventions to rebalance the dopamine motive system might have therapeutic potential for obesity and addiction.

Drug Therapy.

This chapter first summarizes the therapy of addiction disorder, and elaborates on the progress of medication. First, the difference between dependency and addiction are introduced. The basic principles of the therapy of substance and non-substance addiction are then put forward. It is also pointed out in this chapter that with the progress of the study, the goal of addiction disorder therapy is expected to transfer from reducing the relapse and harm of the addiction to completely eliminating and recovering from it. This chapter also introduces the progress of psychological addiction elimination technology, especially the "Unconditioned Stimulus Retrieval Extinction Paradigm and Conditioned Stimulus Retrieval Extinction Paradigm" and PITDH technology. Finally it is pointed out that in addiction disorder therapy, comprehensive intervention has become a trend. With regard to the medication for addiction disorders, this chapter also includes the progress and deficiencies of substance and non-substance addiction. In terms of addiction disorder rehabilitation, the foundation of substance addiction is medication which is, however, limited for non-substance addiction. The key to the rehabilitation of addiction disorder is psycho-behavioral therapy, which is especially effective in eliminating craving.

A narrative review of potential treatment strategies for food addiction.

The concept of food addiction (FA) remains controversial with research being in the nascent stages; FA like any addiction can have a devastating impact on the lives of those afflicted. There exists a clinical need for treatment strategies for those affected. This article reviews potential treatment strategies for FA. The treatment strategies target four core behaviours of the addiction phenotype specifically craving through the opioid system, impulsivity as a personality trait, compulsivity through the serotonergic system and lastly motivation through the dopaminergic system. A range of pharmacological and psychological interventions are reviewed. Future research should seek to test and validate the proposed clinical treatment strategies.

Neurobiological and neuropharmacological aspects of food addiction.

This review aims to draw attention to current studies on syndromes related to food eating behavior, including food addiction, and to highlight the neurobiological and neuropharmacological aspects of food addiction toward the development of new therapies. Food addiction and eating disorders are influenced by several neurobiological factors. Changes in feeding behavior, food addiction, and its pharmacological therapy are related to complex neurobiological processes in the brain. Thus, it is not surprising that there is inconsistency among various individual studies. In this review, we assessed literature including both experimental and clinical studies regarding food addiction as a feeding disorder. We selected articles from animal studies, randomized clinical trials, meta-analyses, narrative, and systemic reviews given that, crucial quantitative data with a measure of neurobiological, neuropharmacological aspects and current therapies of food addiction as an outcome. Thus, the main goal to outline here is to investigate and discuss the association between the brain reward system and feeding behavior in the frame of food addiction in the light of current literature.

The Alpha-1 Adrenergic Receptor Antagonist Prazosin Reduces Binge-Like Eating in Rats.

BACKGROUND: Binge-eating disorder is a pervasive addiction-like disorder that is defined by excessive and uncontrollable consumption of food within brief periods of time. The aim of the current study was to examine the role of the brain noradrenergic system in binge-like eating through the use of the alpha-1 adrenergic receptor antagonist prazosin. METHODS: For this purpose, we employed a limited access model whereby male Wistar rats were allowed to nosepoke for either chow (Chow rats) or a sugary, highly palatable food (Palatable rats) for 1 h/day. The effects of prazosin (0, 0.5, 1 and 2 mg/kg, i.p.) were tested in a fixed ratio 1 (FR1) and progressive ratio (PR) schedule of reinforcement. RESULTS: The results show that prazosin preferentially reduced the responses for palatable food in a FR1 reinforcement schedule; when tested in a PR schedule of reinforcement, prazosin increased breakpoint in both Chow and Palatable rats, but more potently and more efficaciously in the latter. Our results suggest that prazosin treatment preferentially increased the motivational properties of the palatable diet. CONCLUSIONS: The current findings provide the characterization of the effects of prazosin on binge-like eating and offer support to the existing literature showing the important role of the noradrenergic system in addiction-like behavior.

Psychopathological disorders in Prader-Willi syndrome. / Alteraciones psicopatológicas en el síndrome de Prader-Willi.

Prader-Willi syndrome is a genetic disorder caused by chromosomal changes in segment 15q11-q13 including cognitive, mental, and behavioral symptoms, as well as a specific physical phenotype. Both the most common psychopathological changes (intellectual disability, obsessions, impulsivity, autism spectrum disorders, self-injuries) and the main psychiatric comorbidities (affective disorders, psychosis, obsessive-compulsive disorder, autism spectrum disorder) are characterized by a great heterogeneity, which warrants the need for better identification of their frequency and clinical signs. In addition to its effects on body compositionand hypotony, growth hormone has been shown to be useful for regulating patient behavior, and psychoactive drugs are also an option. Other alternatives have shown promising results in experimental trials. Adequate understanding of the psychopathology associated to Prader-Willi syndrome would allow for improving clinical approach, symptom identification, detection of comorbidities, and administration of more effective treatments, leading to better clinical outcomes.